In the
philosophy of perception
The philosophy of perception is concerned with the nature of Perception, perceptual experience and the status of sense data, perceptual data, in particular how they relate to beliefs about, or knowledge of, the world.cf. http://plato.stanford.ed ...
and
philosophy of mind
Philosophy of mind is a branch of philosophy that deals with the nature of the mind and its relation to the Body (biology), body and the Reality, external world.
The mind–body problem is a paradigmatic issue in philosophy of mind, although a ...
,
direct
Direct may refer to:
Mathematics
* Directed set, in order theory
* Direct limit of (pre), sheaves
* Direct sum of modules, a construction in abstract algebra which combines several vector spaces
Computing
* Direct access (disambiguation), ...
or naïve realism, as opposed to indirect or representational realism, are differing models that describe the nature of
conscious
Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, a ...
experiences.
[Lehar, Steve. (2000)]
The Function of Conscious Experience: An Analogical Paradigm of Perception and Behavior
, ''Consciousness and Cognition''.[Lehar, Steve. (2000)]
, ''The Function of Conscious Experience''. The debate arises out of the
metaphysical
Metaphysics is the branch of philosophy that examines the basic structure of reality. It is traditionally seen as the study of mind-independent features of the world, but some theorists view it as an inquiry into the conceptual framework of h ...
question of whether the world we see around us is the real world itself or merely an internal perceptual copy of that world generated by our
conscious
Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, a ...
experience.
Indirect perceptual realism is broadly equivalent to the scientific view of
perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...
that subjects do not experience the external world as it really is, but perceive it through the lens of a conceptual framework. Furthermore, indirect realism is a core tenet of the
cognitivism paradigm in
psychology
Psychology is the scientific study of mind and behavior. Its subject matter includes the behavior of humans and nonhumans, both consciousness, conscious and Unconscious mind, unconscious phenomena, and mental processes such as thoughts, feel ...
and
cognitive science
Cognitive science is the interdisciplinary, scientific study of the mind and its processes. It examines the nature, the tasks, and the functions of cognition (in a broad sense). Mental faculties of concern to cognitive scientists include percep ...
. While there is superficial overlap, the indirect model is unlike the standpoint of
idealism
Idealism in philosophy, also known as philosophical realism or metaphysical idealism, is the set of metaphysics, metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, Spirit (vital essence), spirit, or ...
, which holds that only ideas are real, but there are no mind-independent objects.
Conversely, direct perceptual realism postulates that conscious subjects view the world directly, treating concepts as a 1:1 correspondence. Furthermore, the framework rejects the premise that knowledge arrives via a representational medium, as well as the notion that concepts are interpretations of sensory input derived from a real external world.
History
Aristotle
Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...
was the first to provide a description of direct realism. In ''
On the Soul'' he describes how a see-er is informed of the
object itself by way of the
hylomorphic form carried over the intervening material continuum with which the eye is impressed.
In
medieval philosophy,
direct realism was defended by
Thomas Aquinas
Thomas Aquinas ( ; ; – 7 March 1274) was an Italian Dominican Order, Dominican friar and Catholic priest, priest, the foremost Scholasticism, Scholastic thinker, as well as one of the most influential philosophers and theologians in the W ...
.
Indirect realism was popular with several
early modern philosophers, including
René Descartes
René Descartes ( , ; ; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and Modern science, science. Mathematics was paramou ...
,
[John W. Yolton, ''Realism and Appearances: An Essay in Ontology'', Cambridge University Press, 2000, p. 136.] John Locke
John Locke (; 29 August 1632 (Old Style and New Style dates, O.S.) – 28 October 1704 (Old Style and New Style dates, O.S.)) was an English philosopher and physician, widely regarded as one of the most influential of the Enlightenment thi ...
,
[ G. W. Leibniz, and ]David Hume
David Hume (; born David Home; – 25 August 1776) was a Scottish philosopher, historian, economist, and essayist who was best known for his highly influential system of empiricism, philosophical scepticism and metaphysical naturalism. Beg ...
.[The Problem of Perception (Stanford Encyclopedia of Philosophy)]
: "Paraphrasing David Hume (1739...; see also Locke 1690, Berkeley 1710, Russell 1912): nothing is ever directly present to the mind in perception except perceptual appearances."
Locke categorized qualities as follows:
* Primary qualities are qualities which are "explanatorily basic" – which is to say, they can be referred to as the explanation for other qualities or phenomena without requiring explanation themselves – and they are distinct in that our sensory experience of them resembles them in reality. (For example, one perceives an object as spherical precisely because of the way the atoms of the sphere are arranged.) Primary qualities cannot be removed by either thought or physical action, and include mass, movement, and, controversially, solidity (although later proponents of the distinction between primary and secondary qualities usually discount solidity).
* Secondary qualities are qualities that one's experience does not directly resemble; for example, when one sees an object as red, the sensation of seeing redness is not produced by some quality of redness in the object, but by the arrangement of atoms on the surface of the object which reflects and absorbs light in a particular way. Secondary qualities include colour, smell, sound, and taste.
Thomas Reid, a notable member of the Scottish common sense realism was a proponent of direct realism. Direct realist views have been attributed to Baruch Spinoza.
Late modern philosophers, J. G. Fichte and G. W. F. Hegel
Georg Wilhelm Friedrich Hegel (27 August 1770 – 14 November 1831) was a 19th-century German idealism, German idealist. His influence extends across a wide range of topics from metaphysical issues in epistemology and ontology, to political phi ...
followed Kant in adopting empirical realism. Direct realism was also defended by John Cook Wilson in his Oxford
Oxford () is a City status in the United Kingdom, cathedral city and non-metropolitan district in Oxfordshire, England, of which it is the county town.
The city is home to the University of Oxford, the List of oldest universities in continuou ...
lectures (1889–1915). On the other hand, Gottlob Frege
Friedrich Ludwig Gottlob Frege (; ; 8 November 1848 – 26 July 1925) was a German philosopher, logician, and mathematician. He was a mathematics professor at the University of Jena, and is understood by many to be the father of analytic philos ...
(in his 1892 paper " Über Sinn und Bedeutung") subscribed to indirect realism.
In contemporary philosophy, indirect realism has been defended by Edmund Husserl
Edmund Gustav Albrecht Husserl (; 8 April 1859 – 27 April 1938) was an Austrian-German philosopher and mathematician who established the school of Phenomenology (philosophy), phenomenology.
In his early work, he elaborated critiques of histori ...
and Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British philosopher, logician, mathematician, and public intellectual. He had influence on mathematics, logic, set theory, and various areas of analytic ...
.[ Direct realism has been defended by ]Hilary Putnam
Hilary Whitehall Putnam (; July 31, 1926 – March 13, 2016) was an American philosopher, mathematician, computer scientist, and figure in analytic philosophy in the second half of the 20th century. He contributed to the studies of philosophy of ...
, John McDowell
John Henry McDowell (born 7 March 1942) is a South African philosopher, formerly a fellow of University College, Oxford, and now university professor at the University of Pittsburgh. Although he has written on metaphysics, epistemology, anci ...
, Galen Strawson, and John R. Searle
John Rogers Searle (; born July 31, 1932) is an American philosopher widely noted for contributions to the philosophy of language, philosophy of mind, and social philosophy. He began teaching at UC Berkeley in 1959 and was Willis S. and Marion ...
.
However, epistemological dualism has come under sustained attack by other contemporary philosophers, such as Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein ( ; ; 26 April 1889 – 29 April 1951) was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language.
From 1929 to 1947, Witt ...
(the private language argument) and Wilfrid Sellars in his seminal essay "Empiricism and the Philosophy of Mind". Indirect realism is argued to be problematical because of Ryle's regress and the homunculus argument. Recently, reliance on the private language argument and the "homunculus objection" has itself come under attack. It can be argued that those who argue for "inner presence", to use Antti Revonsuo's term, are not proposing a private "referent", with the application of language to it being "private" and thus unshareable, but a ''private'' use of ''public'' language. There is no doubt that each of us has a private understanding of public language, a notion that has been experimentally supported; George Steiner refers to our personal use of language as an " idiolect", one particular to ourselves in its detail. The question has to be put how a collective use of language can go on when, not only do we have differing understandings of the words we use, but our sensory registrations differ.
Arguments against direct realism
Argument from illusion
This argument was "first offered in a more or less fully explicit form in Berkeley ( 1713)." It is also referred to as the problem of conflicting appearances (e.g. Myles Burnyeat's article ''Conflicting Appearances''). It has been argued that "informed commonsense" indicates that perceptions often depend on organs of perception.[Naïve Realism](_blank)
, University of Reading
The University of Reading is a public research university in Reading, Berkshire, England. It was founded in 1892 as the University Extension College, Reading, an extension college of Christchurch College, Oxford, and became University College, ...
. For example, humans would receive visual information very differently if they, like flies, had compound eyes, and may not even be able to imagine how things would appear with entirely different sense organs such as infra-red detectors or echo-location devices. Furthermore, perception systems can misrepresent objects even when in full working order, as shown, for example, by optical illusions like the Müller-Lyer illusion. More dramatically, sometimes people perceive things which are not there at all, which can be termed instances of "hallucination" or "perceptual delusion".
The argument from illusion allegedly shows the need to posit sense-data as the immediate objects of perception. In cases of illusion or hallucination
A hallucination is a perception in the absence of an external stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming ( REM sleep), which does not involve wakefulness; pse ...
, the object has qualities that no public physical object in that situation has and so must be distinct from any such object.[ Naïve realism may accommodate these facts as they stand by virtue of its very vagueness (or "open-texture"): it is not specific or detailed enough to be refuted by such cases.][ A more developed direct realist might respond by showing that various cases of misperception, failed perception, and perceptual relativity do not make it necessary to suppose that sense-data exist. When a stick submerged in water looks bent a direct realist is not compelled to say the stick actually is bent but can say that the stick can have more than one appearance: a straight stick can look bent when light reflected from the stick arrives at one's eye in a crooked pattern, but this appearance is not necessarily a sense-datum in the mind. Similar things can be said about the coin which appears circular from one vantage point and oval-shaped from another. Pressing on your eyeball with a finger creates double vision but assuming the existence of two sense-data is unnecessary: the direct realist can say that they have two eyes, each giving them a different view of the world. Usually the eyes are focused in the same direction; but sometimes they are not.
However, this response is presumably based on previously observed data. If one were to be able to observe nothing other than the stick in the water, with no previous information, it would appear that the stick was bent. Visual depth in particular is a set of inferences, not an actual experience of the space between things in a radial direction outward from the observation point. If all ]empirical evidence
Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law.
There is no general agreement on how the ...
is based upon observation then the entire developed memory and knowledge of every perception and of each sense may be as skewed as the bent stick. Since objects with different qualities are experienced from each of the different perspectives there is no apparent experiential basis for regarding one out of any such set of related perceptual experiences as the one in which the relevant physical object is itself immediately experienced. The most reasonable conclusion is that the experienced object is always distinct from the physical object or at least that there is no way to identify which, if any, of the immediately experienced objects is the physical object itself. Epistemologically it is as though physical objects were never given, whether or not that is in fact the case.[
Another potential counter-example involves vivid hallucinations: phantom elephants, for instance, might be interpreted as sense-data. A direct realist response would differentiate hallucination from genuine perception: no perception of elephants is going on, only the different and related mental process of hallucination. However, if there are visual images when we hallucinate it seems reasonable that there are visual images when we see. Similarly if dreaming involves visual and auditory images in our minds it seems reasonable to think there are visual and auditory images, or sense-data, when we are awake and perceiving things. This argument has been challenged in a number of different ways. First it has been questioned whether there must be some object present that actually has the experienced qualities, which would then seemingly have to be something like a sense-datum. Why couldn't it be that the perceiver is simply in a state of seeming to experience such an object without any object actually being present? Second, in cases of illusion and perceptual relativity there is an object present which is simply misperceived, usually in readily explainable ways, and no need to suppose that an additional object is also involved. Third, the last part of the perceptual relativity version of the argument has been challenged by questioning whether there is really no experiential difference between veridical and non-veridical perception; and by arguing that even if sense-data are experienced in non-veridical cases and even if the difference between veridical and non-veridical cases is, as claimed, experientially indiscernible, there is still no reason to think that sense-data are the immediate objects of experience in veridical cases. Fourth, do sense-data exist through time or are they momentary? Can they exist when not being perceived? Are they public or private? Can they be themselves misperceived? Do they exist in minds or are they extra-mental, even if not physical? On the basis of the intractability of these questions, it has been argued that the conclusion of the argument from illusion is unacceptable or even unintelligible, even in the absence of a clear diagnosis of exactly where and how it goes wrong.][
Direct realists can potentially deny the existence of any such thing as a mental image but this is difficult to maintain, since we seem able to visually imagine all sorts of things with ease. Even if perception does not involve images other mental processes like imagination certainly seem to. One view, similar to Reid's, is that we do have images of various sorts in our minds when we perceive, dream, hallucinate and imagine but when we actually perceive things, our sensations cannot be considered objects of perception or attention. The only objects of perception are external objects. Even if perception is accompanied by images, or sensations, it is wrong to say we perceive sensations. Direct realism defines perception as perception of external objects where an "external object" is allowed to be a photon in the eye but not an impulse in a nerve leading from the eye. Recent work in neuroscience suggests a shared ontology for perception, imagination and dreaming, with similar areas of brain being used for all of these.
The character of experience of a physical object can be altered in major ways by changes in the conditions of perception or of the relevant sense-organs and the resulting neurophysiological processes, without change in the external physical object that initiates this process and that may seem to be depicted by the experience. Conversely any process that yields the same sensory/neural results will yield the same perceptual experience, no matter what the physical object that initiated the process may have been like. Furthermore, the causal process that intervenes between the external object and the perceptual experience takes time, so that the character of the experience reflects, at the most, an earlier stage of that object than the one existing at the moment of perception. As in observations of astronomical objects the external object may have ceased to exist long before the experience occurs. These facts are claimed to point to the conclusion that the direct object of experience is an entity produced at the end of this causal process, distinct from any physical object that initiates the process."][Epistemological Problems of Perception](_blank)
, Stanford Encyclopedia of Philosophy.
Arguments against indirect realism
One concern with indirect realism is that if simple data flow and information processing is assumed then something in the brain must be interpreting incoming data. This something is often described as a homunculus, although the term homunculus is also used to imply an entity that creates a continual regress, and this need not be implied. This suggests that some phenomenon other than simple data flow and information processing is involved in perception. This is more of an issue now than it was for rationalist philosophers prior to Newton, such as Descartes, for whom physical processes were poorly defined. Descartes held that there is a "homunculus" in the form of the soul, belonging to a form of natural substance known as '' res cogitans'' that obeyed different laws from those obeyed by solid matter ('' res extensa''). Although Descartes' duality of natural substances may have echoes in modern physics (Bose and Fermi statistics) no agreed account of 'interpretation' has been formulated. Thus representationalism remains an incomplete description of perception. Aristotle realized this and simply proposed that ideas themselves (representations) must be aware—in other words that there is no further transfer of sense impressions beyond ideas.
A potential difficulty with representational realism is that, if we only have knowledge of representations of the world, how can we know that they resemble in any significant way the objects to which they are supposed to correspond? Any creature with a representation in its brain would need to interact with the objects that are represented to identify them with the representation. This difficulty would seem reasonably to be covered by the learning by exploration of the world that goes on throughout life. However, there may still be a concern that if the external world is only to be inferred, its 'true likeness' might be quite different from our idea of it. The representational realist would answer to this that "true likeness" is an intuitive concept that falls in the face of logic, since a likeness must always depend on the way in which something is considered.
A semantic difficulty may arise when considering reference
A reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to ''refer to'' the second object. It is called a ''nam ...
in representationalism. If a person says "I see the Eiffel Tower" at a time when they are indeed looking at the Eiffel Tower, to what does the term "Eiffel Tower" refer? The direct realist might say that in the representational account people do not really see the tower but rather 'see' the representation. However, this is a distortion of the meaning of the word "see" which the representationalist does not imply. For the representationalist the statement refers to the Eiffel Tower, which implicitly is experienced in the form of a representation. The representationalist does not imply that when a person refers to the Eiffel Tower, they are referring to their sense experience, and when another person refers to the Tower, they are referring to their sense experience.
Furthermore, representative realism claims that we perceive our perceptual intermediaries—we can attend to them—just as we observe our image in a mirror. However, as we can scientifically verify, this is clearly not true of the physiological components of the perceptual process. This also brings up the problem of dualism and its relation to representative realism, concerning the incongruous marriage of the metaphysical and the physical.
The new objection to the Homunculus Argument claims that it relies on a naive view of sensation. Because the eyes respond to light rays, there is no reason for supposing that the visual field requires eyes to see it. Visual sensation (the argument can be extrapolated to the other senses) bears no direct resemblance to the light rays at the retina, nor to the character of what they are reflected from or pass through or what was glowing at the origin of them. The reason given is that they only bear the similarities of ''co-variation'' with what arrives at the retinas. Just as the currents in a wire going to a loudspeaker vary proportionately with the sounds that emanate from it but have no other likeness, so too does sensation vary proportionately (and not necessarily directly) with what causes it but bears no other resemblance to the input. This implies that the colour we experience is actually a cortical occurrence, and that light rays and external surfaces are not themselves coloured. The proportional variations with which cortical colour changes are there in the external world, but not colour as we experience it. Contrary to what Gilbert Ryle believed, those who argue for sensations being brain processes do not have to hold that there is a "picture" in the brain since this is impossible according to this theory since actual pictures in the external world are not coloured. It is plain that Ryle unthinkingly carried over what the eyes do to the nature of sensation; A. J. Ayer at the time described Ryle's position as "very weak". So there is no "screen" in front of cortical "eyes", no mental objects before one. As Thomas Hobbes
Thomas Hobbes ( ; 5 April 1588 – 4 December 1679) was an English philosopher, best known for his 1651 book ''Leviathan (Hobbes book), Leviathan'', in which he expounds an influential formulation of social contract theory. He is considered t ...
put it: "How do we take notice of sense?—by sense itself". Moreland Perkins has characterized it thus: that sensing is not like kicking a ball, but rather "kicking a kick". Today there are still philosophers arguing for colour being a property of external surfaces, light sources, etc.
A more fundamental criticism is implied in theories of this type. The differences at the sensory and perceptual levels between agents require that some means of ensuring at least a partial correlation can be achieved that allows the updatings involved in communication to take place. The process in an informative statement begins with the parties hypothetically assuming that they are referring to the "same" entity or "property", even though their selections from their sensory fields cannot match; we can call this mutually imagined projection the "logical subject" of the statement. The speaker then produces the logical predicate which effects the proposed updating of the "referent". If the statement goes through, the hearer will now have a different percept and concept of the "referent"—perhaps even seeing it now as two things and not one. The radical conclusion is that we are premature in conceiving of the external as already sorted into singular "objects" in the first place, since we only need to behave ''as if'' they are already logically singular. The diagram at the beginning of this entry would thus be thought of as a false picture of the actual case, since to draw "an" object as already selected from the real is only to treat the practically needful, but strictly false, hypothesis of objects-as-logically-singular as ontologically given. The proponents of this view thus argue that there is no need actually ''to believe'' in the singularity of an object since we can manage perfectly well by ''mutually imagining'' that 'it' is singular. A proponent of this theory can thus ask the direct realist why he or she thinks it is necessary to move to taking the imagining of singularity for real when there is no practical difference in the outcome in action. Therefore, although there are selections from our sensory fields which for the time being we treat as if they were objects, they are only provisional, open to corrections at any time, and, hence, far from being direct ''representations'' of pre-existing singularities, they retain an experimental character. Virtual constructs or no, they remain, however, selections that are causally linked to the real and can surprise us at any time—which removes any danger of solipsism in this theory. This approach dovetails with the philosophy known as social constructivism
Social constructivism is a sociological theory of knowledge according to which human development is socially situated, and knowledge is constructed through interaction with others. Like social constructionism, social constructivism states that ...
.[Glasersfeld, Ernst von (1995), ''Radical Constructivism: A Way of Knowing and Learning,'' London: RoutledgeFalmer.]
Adverbial theory
The above argument invites the conclusion of a perceptual dualism that raises the issue of how and whether the object can be known by experience. The adverbial theory proposes "that this dualism is a dualism of ''objects'', with perceptual experience being a more direct experience of objects of a different sort, sense-data." Perceptual dualism implies:both an ''act'' of awareness (or apprehension) and an ''object'' (the sense-datum) which that act apprehends or is an awareness of. The fundamental idea of the adverbial theory, in contrast, is that there is no need for such objects and the problems that they bring with them (such as whether they are physical or mental or somehow neither). Instead, it is suggested, merely the occurrence of a mental act or mental state with its own intrinsic character is enough to account for the character of immediate experience.
According to the adverbial theory, when, for example, I experience a silver elliptical shape (as when viewing a coin from an angle) I am in a certain specific state of sensing or sensory awareness or of being appeared to: I sense in a certain manner or am appeared to in a certain way, and that specific manner of sensing or of being appeared to accounts for the content of my experience: I am in a certain distinctive sort of experiential state. There need be no object or entity of any sort that is literally silver and elliptical in the material world or in the mind. I experience a silver and elliptical shape because an object or entity that literally has that color and shape is directly before my mind. But the nature of these entities and the way in which they are related to the mind are difficult to understand. The adverbial theory has the advantage of being metaphysically simpler, avoiding issues about the nature of sense-data, but we gain no real understanding of the nature of the states in question or of how exactly they account for the character of immediate experience."
See also
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References
External links
Online papers on representationalism
by various authors, compiled by David Chalmers
This is a simulation
- A short article, aimed at the general public, arguing for the representative theory of perception.
* Harold I. Brown, "Direct Realism, Indirect Realism, and Epistemology". Philosophy and Phenomenological Research, Vol. 52, No. 2. (Jun., 1992), pp. 341–363.
What Do We Perceive and How Do We Perceive It? (PDF file)
* McCreery, C. (2006) "Perception and Hallucination: the Case for Continuity.” Oxford: Oxford Forum
An analysis of empirical arguments for representationalism. Online PDF
{{epistemology
Cognitive science
Philosophy of perception
Epistemological theories
Metaphysical realism
Dualism (philosophy of mind)
Theory of mind
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